The boys learn how to make rockets by using trial and error. At the time, there are no directions to guide them and no safety manual. The boys do not even have a book until their chemistry teacher gives them one in chapter 13.
The boys break several fire safety rules while handling the rockets. On Sonny's first attempt, he blows up his mom's fence. Later, the boys measure explosions by filling pop bottles with their black powder. The use of alcohol as rocket fuel causes the rockets to explode. The rockets also put people in danger because of the unpredictability of where they fly. This is concerning to the community, because everyone believes that the boys are jeopardizing people's safety.